Edge sealing means for filter rollers



Nov. 1, 1966 I FLOYD 3,282,034

EDGE SEALING MEANS FOR FILTER ROLLERS Filed Nov. 5, 1962 INVENTOR mesa/5E Fur/9 ATTORNEY United States Patent 3,282 034 EDGE FsEAiZING MEANSEGR FILTER RGLLERS Frederick Floyd, 1.0T Watling Sh, fitrood, England Filed Nev. 5, 1962, Ser. No. 235,333 8 Elaims. (Cl. 55-354) This invention relates to improvements in filters, and especially, but not exclusively, to filters of the kind described in my US. Patent No. 3,045,410 granted July 24, 1962. In the specification of said patent there is described a filter having a web of filter material provided with beaded edges to co-operate with grooves on the ends of rollers rotatable within a casing, the beads, rollers, and casing together forming a fluid-tight seal as the rollers are pressed against each other under tension of the filter material as it is wound on to a take-up roll.

It has been found in practice under certain operating conditions, for example, when the filter is fitted close to a heater battery, that the radiant heat from this source is sufficient to shrink enough of the filter material as to partially destroy the edge seal which has been found otherwise successful.

It is an object of the invention to provide an arrangement that will maintain the edge sealing under adverse conditions.

According to the invention, a filter having at least two rollers providing an extended path within a casing for a web of fil-ter material has each end of each roller provided with a flexible member arranged to bear outwardly against the casing and against the flexible member of an adjoining roller, whereby the edge of the web is pinched between the flexible members and an edge seal is provided.

The flexible members may be in the form of skirts secured to the ends of the rollers and arranged to be spread outwardly. The flexible skirts may be formed of felt, or rubber, or plastic.

Alternatively, the flexible members may be in the form of resilient rings partly housed in cut back portions of the rollers at their ends.

Embodiments of the invention will be described with reference to the accompanying drawings, in which:

FIGURE 1 is a fragmentary diagrammatic side elevation, partly sectioned, of the ends of a pair of rollers in one embodiment in a filter casing,

FIGURE 2 is a diagrammatic showing of the wiping paths of the rollers of FIGURE 1,

FIGURE 3 is a fragmentary diagrammatic side elevation, partly sectioned, of the ends of a pair of rollers in another embodiment, and,

FIGURE 4 is a fragmentary detail View of the rollers of FIGURE 3, showing the seal thereof.

Referring to FIGURES 1 and 2, the general arrangement of the filter casing 10, rollers 11 and 12, and web 13 of filter material are the same as described in my aforementioned patent.

Each roller has a cylindrical wall 14 and two ends caps 15, secured to the cylindrical wall 14 in any desired manner. The general construction of the rollers is notof importance to the invention. Each end cap 15 has a flat end 15a and a cylindrical wall 15b, these being joined by a chamfered portion 150.

Each roller is provided at its end with a flexible skirt 16. This has one end 16a of smaller diameter closely embracing the cylindrical wall 15b of the end cap 15 of the roller, before the chamfering begins, and secured to said wall 15b. The other end 16b of the skirt is flared outwardly so that its free edge is turned through 90 to lie against the adjacent wall of the casing 10. Conveniently the skirt 16 is moulded, e.g., from rubber or plastic, or felt or bristle obtainable in the strip and formed into the desired shape so as to be a snug fit on the end cap 15. The diameter of the out-turned end of the skirt Fatented Nov. I, 1966 15b is such that it just touches the corresponding edge of the skirt 16b on the adjoining roller, as shown in FIGURE In operation, as the filter material 13 is drawn through the filter and the rollers 11, 12 are rotated, the skirts 16b press against the casing 10 and Wipe the sides of the easing, at the same time compressing the edge of the filter material so as to provide the desired edge seal. The annular areas designated 16b in FIGURE 2 represent the areas of the skirts in sealing contact with the wall of the casing 10.

In another embodiment illustrated in FIGURES 3 and 4, the rollers 11 and 12 have chamfered end caps 15 as before. In the groove formed by each chamfered portion and the adjacent wall of the casing 18 there lies a rubber ring 17 of circular cross-section and having an outside diameter slightly greater than that of the roller 11 or 12. The rubber rings 17 on adjacent rollers are arranged just to touch, as shown in FIGURE 4. They need not be secured -to their associated rollers.

In operation, the rings of the adjacent rollers 11, 12 tend to pinch the edge of the filter 13 between them, and also bear on the wall of the casing 10, providing a wiping path and an edge seal.

I claim:

1. In a filter having a casing with side walls and a web of filter material to pass through said casing; rollers between which the filter material passes extending between the side Walls and terminating at their end portions closely adjacent the side walls and pinching and compressing the edges of the web adjacent the side walls, each roller having a flexible wall contact member arranged to bear outwardly against a side wall of the casing and against the flexible member of an adjoining roller, the edge of the web being compressed between the flexible members.

2. A filter as claimed in claim I, the flexible members being in the form of skirts secured to the ends of the rollers and arranged to be spread outwardly.

3. A filter as claimed in claim 1, the flexible skirts being formed of flexible sheet plastic material.

4. A filter as claimed in claim 1, the flexible members being in the form of resilient rings and the ends of the rollers having recesses receiving the rings.

5. In a web filter having a side wall casing; a pair of parallel axis closely adjacent rollers between which a web filter is engaged, said rollers having their ends positioned closely adjacent the wall and having circular flexible sealing members pressing against the edges of the filter and against the wall.

6. The filter of claim 5, said members consisting of outwardly flaring skirts contacting the wall and encircling the ends of the rollers.

7. The filter of claim 5, said members consisting of circular cross section rubber rings contacting the wall, the ends of the rollers and the edges of the web.

The filter of claim 5, said rollers having cup shaped end caps having flat end walls parallel to the walls with bevelled edges and sealing means contacting said end caps, the edges of said web and said wall around said end caps.

References (Cited by the Examiner UNITED STATES PATENTS 3,045,410 7/1962 Floyd 55352 FOREIGN PATENTS 1,231,871 4/1960 France. 1,240,402 7/ 1960 France.

511,455 8/ 1939 Great Britain. 592,912 5/ 1959 Italy.

HARRY B. THORNTON, Primary Examiner. 

1. IN A FILTER HAVING A CASING WITH SIDE WALLS AND A WEB OF FILTER MATERIAL TO PASS THROUGH SAID CASING; ROLLERS BETWEEN WHICH THE FILTER MATERIAL PASSES EXTENDING BETWEEN THE SIDE WALLS AND TERMINATING AT THEIR END PORTION CLOSELY ADJACENT THE SIDE WALLS AND PINCHING AND COMPRESSING THE EDGES OF THE WEB ADJACENT THE SIDE WALL, EACH ROLLER HAVING A FLEXIBLE WALL CONTACT MEMBER ARRANGED TO BEAR OUTWARDLY AGAINST A SIDE WALL OF THE CASING AND AGAINST THE FLEXIBLE MEMBER OF AN ADJOINING ROLLER, THE EDGE OF THE WEB BEING COMPRESSED BETWEEN THE FLEXIBLE MEMBERS. 